Foundations of Physics (2019) 1-38, in Press DOI: 10.1007/s10701-019-00236-4 Quaternion algebra on 4D superfluid quantum space-time. Gravitomagnetism Valeriy I. Sbitnev January 29, 2019 Abstract Gravitomagnetic equations result from applying quaternionic dif- ferential operators to the energy-momentum tensor. These equations are sim- ilar to the Maxwell's EM equations. Both sets of the equations are isomor- phic after changing orientation of either the gravitomagnetic orbital force or the magnetic induction. The gravitomagnetic equations turn out to be parent equations generating the following set of equations: (a) the vorticity equation giving solutions of vortices with nonzero vortex cores and with infinite lifetime; (b) the Hamilton-Jacobi equation loaded by the quantum potential. This equa- tion in pair with the continuity equation leads to getting the Schr¨odingerequa- tion describing a state of the superfluid quantum medium (a modern version of the old ether); (c) gravitomagnetic wave equations loaded by forces acting on the outer space. These waves obey to the Planck's law of radiation. Keywords superfluid quantum vacuum · gravitomagnetic · electromag- netism · wave function · vorticity · vortex · cosmic microwave radiation 1 Introduction Roger Penrose in his earlier works [65,66] has proposed the formalism of twistor algebra where four parameters of the space-time, t; x; y; z, by amazing man- ner find accordance with spinor group SU(2). Twistor theory was originally proposed as a new geometric framework for physics that aims to unify general relativity and quantum mechanics [6]. An unexpected interconnection between V. I. Sbitnev St. Petersburg B. P. Konstantinov Nuclear Physics Institute, NRC Kurchatov Institute, Gatchina, Leningrad district, 188350, Russia; Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA 94720, USA arXiv:1901.09098v1 [gr-qc] 21 Jan 2019 Tel.: +781-37-137944 E-mail: [email protected] 2 Valeriy I. Sbitnev the geometry of Minkowski space-time and the twisting of space-time leads to a new view of the relation between quantum theory and space-time curvature. A basic type of the twistor with four complex components is given by a pair of two-component spinors, one of which defines the direction and the other defines its angular moment about the origin. Components of Minkowski space are subjected to the complexification in order to use a powerful apparatus of the unitary unimodular group SU(2). Here we pass from the group SU(2) to its quaternion representation through the real 4×4 matrices and transform Penrose's twistor ideas for using the Clif- ford algebra. In fact, we consider motions on the ten-dimensional space-time manifold by applying the Clifford algebra [8,29,49,37]. It turns out, that the quaternion 4 × 4 matrices allow also to describe, in addition to the transla- tion of the space-time, the appearance of torsion fields [67,74{76,102]. Similar type of the torsion, the Cartan's torsion, which was put into oblivion, was under consideration of Schr¨odinger, Einstein, Dirac at developing a unified field theory [30,31,36]. Clifford algebras are important mathematical tools in the knowledge of the subtle secrets of Nature. This compliance is marked by many authors in special literature devoted to this issue [8,28,29,37,49,74,100]. The quaternions serve as a tool for describing both translations in 4D space and spin rotations on 3D spheres of unit radius [2]. The Lorentz transformations of 4D space-time is described through the quaternion matrices as well [98]. Roger Penrose and Wolfgang Rindler devoted two books to this issue, both entitled "Spinors and Space-Time" [68,69] in which the above were considered in details. Here we deal with the space densely filled by an incompressible quan- tum superfluid described as a Bose-Einstein condensate [38,39,111,89]. At low temperature of the cosmic space, the vacuum energy density scales as non-relativistic matter [4,3]. In this perspective, computations lead to the gravitomagnetic equations [56] strongly similar to the Maxwell's equations for electromagnetic fields. The Schr¨odinger , vorticity equations, and wave equa- tions follow from these equations as a natural outcome. The article is organized as follows. Sec. 2 considers the continuity equation on 3D Euclidean space with three translations along axes x; y; z and three rotations about these axes. Here we introduce 6D space having six degrees of freedom due to three translations along axes x; y; z and three rotations about these axes. Here we go on from the SU(2) group to the quaternion group of 4 × 4 matrices for describing motions in 10D space (6+4 degrees of freedom) and introducing the balance equation in it. In Sec. 3 we define the energy- momentum tensor and further based on the quaternion algebra we define dif- ferential shift operators by using four quaternion matrices. As a result of acting these operators on the energy-momentum tensor we get the force density ten- sor containing the irrotational force densities and orbital ones. In Sec. 4 we get a set of the gravitomagnetic equations that are similar to Maxwell's equa- tions of the electromagnetic field. In Sec. 5 we derive from the gravitomagnetic equations three equations, namely: (subsec. 5.1) the Schr¨odingerequation (in particular, we consider here deceleration of a baryon-matter object in a cosmic Quaternion algebra on 4D superfluid quantum space-time. Gravitomagnetism 3 space), (subsec. 5.2) the vorticity equation (we consider here the neutron spin resonance experiment combined with the spin-echo spectroscopy for measur- ing gravitomagnetic effects), and (subsec. 5.3) the wave equations describing gravitomagnetic waves in the superfluid quantum space-time. In Sec. 6 we con- sider the cosmic microwave background radiation and its connection with the gravitomagnetic waves. Sec. 7 summarizes the results. 2 Balance equation in 6D space Let us discuss the degrees of freedom of our 3D space. Around each point (x; y; z) of the space one can mentally describe the sphere of unit radius. It can mean that any rotation of the unit vector describes some path on the surface of the unit sphere with its origin fixed at the point (x; y; z). We know that a pseudovector is the mathematical image of a gyro. A gyro bundle containing the gyros with different inertial masses will show scatter- ing the pseudovector tips on the unit sphere surface at their rotations. By combining the distribution of locations of the gyros in 3D space, R3, with the distribution of vertices of their pseudovectors on surface of 3D sphere, S3, we come to the joint distribution of these rotating objects in 6D space R6 = R3⊗S3, Fig. 1. Fig. 1 6D space R6 = R3⊗S3 consists of 3D space R3, where around each point (x; y; z) 2 R3 rotation of a gyro is allowed along any arc laying on 3D sphere S3. Distances δx, δy, δz between these centers of the spheres tend to such minimal values as possible. We begin first from definition of a joint amplitude distribution of the translations and rotations on the space R6 = R3 ⊗ S3 that we record as RR(r; t) = R(r; t)j'(r; t)i. Here R(r; t) is the amplitude distribution of the 4 Valeriy I. Sbitnev translation flows in space R3 and j'(r; t)i is the amplitude distribution of ro- tation flows on the sphere S3. Note that translations and rotations are differ- ent forms of motion. The first is irrotational form, while the second is orbital. That's why we take a direct product of R(r; t) and j'(r; t)i. Let us define a generator D(v) that realizes a small shift of RR(r; t) by δτ on the space R6: RR(r; t + δτ) = D(u)RR(r; t): (1) It is a balance equation. The generator D(u) transforms the amplitude distri- bution of the spin flows [2,90,98], but does not act on the amplitude distribu- tion R(r; t). It looks as follows D(u) = u0σ0 + iuxσx + iuyσy + iuzσz: (2) Here i is the imaginary unit. Four basic matrices in this expression, namely, three Pauli matrices, σx, σy, and σz, and the unit matrix σ0 read: 0 1 0 −i 1 0 1 0 σ = ; σ = ; σ = ; σ = : (3) x 1 0 y i 0 z 0 −1 0 0 1 The matrices submit to the following commutation relations σxσy = −σyσx = iσz; σyσz = −σzσy = iσx; 2 2 2 σzσx = −σxσz = iσy; σx = σy = σz = σ0 (4) As a result, the shifting transformation (1) can be reduced to two equations: d ρ(r; t) = 0; (5) d t '(r; t + δτ)i = D(u)'(r; t)i: (6) Here ρ(r; t) = R2(r; t) is the density distribution of sub-quantum particles, carriers of masses. Therefore, Eq. (5) is the continuity equation. It says that there are neither sources nor sinks in the space R3. While Eq. (6) implies existence of external fields that perturb motions of spins [2]. The above transformation associates the translation on the space R3 with the rotations of the sphere S3 of unit radius with applying the unitary uni- modular group SU(2) [34,68]. For a more complete creative perception of these transformations, it makes sense to go to the quaternion representation of the motions - to set of real 4×4 matrices. 2.1 Quaternion representation The generators D(u) and D(s) belong to the group SU(2). Then their multi- plication D(~s) = D(u) ·D(s) ) (~s0σ0 + is~xσx + is~yσy + is~zσz) (7) = (u0σ0 + iuxσx + iuyσy + iuzσz) · (s0σ0 + isxσx + isyσy + iszσz) Quaternion algebra on 4D superfluid quantum space-time.